How are behavioral sequences learned and integrated? The proposed research will investigate non-verbal mechanisms underlying serially organized behavior by studying its cognitive development in monkeys. This strategy eliminates two factors that complicate the study of serially organized behavior in human subjects: language and experience with serial tasks. The investigation of serial learning animals also provides a comparative perspective of mechanisms of serially organized behavior. How behavioral sequences are learned and integrated will be studied with two recently developed techniques for training monkeys to produce and recall lists of arbitrary and numerical stimuli. In the simultaneous chaining paradigm, all of the stimuli and opportunities to respond are available simultaneously, a key feature of serial tasks used in verbal learning experiments on human subjects. Since their configuration is changed from trail to trial subjects must rely on a representation of their ordinal position while executing the required sequence. Short-term serial memory will be studied with a delayed-matching-to-successive-samples paradigm in which the subject is required to reproduce the list displayed as the sample as a simultaneous chain. Some lists will provide real-time measures of mechanisms underlying sequential behavior. Another unusual feature of the proposed research is the extensive experience of many of the subjects in performing serial tasks with arbitrary and numerical stimuli. The experiments will be conducted with touch-sensitive video monitors that allow the experimenter to select list items from thousands of digitized. The nature of representations that mediate sequence production will be studied by: (1) determining how serial expertise develops; (2) assessing a monkey's ability to "chunk" sequences it recognizes and/or produces; (3) assessing subjects' knowledge of the ordinal position of items in a list; (4) measuring the subjective organization of list items in short-term serial memory; and (5) comparing numerical and symbolic distance effects. The results of these experiments will provide non-verbal models of serial learning. The proposed research will also have two important interdisciplinary ramifications: (1) it can provide preparations for studying the neural control of serially organized behavior; and (2) the non-verbal serial tasks that will be used with monkeys could also be used with pre-verbal children in ways that would reveal the contributions that language adds to basic serial skills.